Calcite (Cobalt-bearing)

Item Description

Calcite is one of those minerals that is found in a multitude of colors, largely due to the fact that the nature of the species allows for many chromophore inclusions. One of the most vibrant chromophores in the mineral world is cobalt, which can create intense hues in many species, especially Calcite. The rich fuchsia / pink colors seen in cobalt-bearing Calcite specimens from multiple localities around the world is unmistakable, and the pieces from the Agdz Cercle in Morocco, e.g. (Agoudal, Bou Azzer, Aghbar, etc.) are some of the most iconic examples of the material ever seen. This piece is a gorgeous small cabinet filled with wonderfully gemmy, well-formed, scalenohedral crystals measuring up to 8 mm, showing vivid purplish-pink hues, which range to more of a reddish-pink in spots. The crystals have a pleasing almost chatoyant vitreous luster when rotated in the light. No major damage I can find, and it's very eye-catching in person. Minor steel-grey metallic crystals of an unknown species can be seen on the lower edge of one side of the piece, and after looking at the reported minerals from Agoudal on mindat.org, the only thing that seems to match is Alloclasite, but this is merely speculation, the crystals likely would need to be analyzed to know their identity. Still a really choice display specimen of this beautiful and classic material.
From the collection of Albert M. “Al” Liebetrau (1938-2023) and Suzanne "Sue" Liebetrau (# 3216).
Both Al and Sue were from Wisconsin originally, but lived in various places in the US and Europe, eventually ending up in Oregon. Al was a teacher (from high school to the university level) and statistician with degrees in math and statistics, and Sue taught English and worked as a technical editor for Battelle Memorial Institute. While Al has since passed away, Sue is still a very active member of the mineral collecting community. The Liebetraus were married for over 60 years (they were married in 1960) and assembled a world-class collection of fine quality crystallized display specimens, along with one of the great fluorescent mineral collections in the United States. Incidentally, Al was the former president of the Fluorescent Mineral Society, and was the main person in charge of putting together the massive number of displays at the 2021 Tucson Show (fluorescent minerals was the theme that year).
Mineral specimens from their collection have won multiple awards at various shows, including the prestigious Lidstrom Trophy for the best mineral specimen at the TGMS Show in Tucson, along with the Desautels Trophy for the best case. Additionally, the Liebetraus were awarded the Romero Award for best Mexican specimen, and the Bideaux Trophy for best Arizona specimen.
You can read more about Al and Sue and their lives at the following link: https://www.tandfonline.com/doi/full/10.1080/00357529.2023.2236000